


I Never Say Goodbye

by TooManyIdeas (XionKuriyama)



Category: Kingdom Hearts, 境界の彼方 | Kyoukai no Kanata | Beyond the Boundary
Genre: Action, Action & Romance, Alternate Universe - Canon Divergence, Angst, Angst with a Happy Ending, Awkwardness, Crossover, Crossover Pairings, Depression, Dorks, Drama & Romance, Emotional Hurt/Comfort, F/M, Fluff and Angst, Friendship, Friendship/Love, Game: Kingdom Hearts 358/2 Days, Gen, Happy Ending, Hurt/Comfort, Other Additional Tags to Be Added, Romance, Stalking, Teen Romance, these characters are utter dorks omg
Language: English
Status: In-Progress
Published: 2018-09-25
Updated: 2018-09-27
Packaged: 2019-07-17 15:19:50
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,540
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16098347
Author URL: https://archiveofourown.org/users/XionKuriyama/pseuds/TooManyIdeas
Summary: Roxas and Xion are sent to the Spirit World, where they find themselves befriending some of the locals, despite the Organization XIII directive against such. Specifically, an immortal half-Youmu named Akihito and a clumsy pink-haired warrior named Mirai. But this world is turning without them, and things are already in motion that could bring the friendship to a tragic end so soon after it has begun. Takes place during 358/2 Days after Xion gets her Keyblade back but before she fights Riku (for Kingdom Hearts) and during the original anime starting in the middle of the first episode (for KnK).





	1. Chapter 1

**Author's Note:**

> So, this is an idea I've had in my head for a while. I love both KH and Beyond the Boundary, and I hope I can introduce at least a few people to KnK/BtB, which seriously needs more fics. Please, go watch it, it's amazing and short. :) Remember, kudos and comments are always appreciated. Enjoy!
> 
> DISCLAIMER: Kingdom Hearts belongs to Disney and Square Enix. Kyoukai no Kanata (Beyond the Boundary) belongs to Nagomu Torii and Kyoto Animation. I do not stand to profit from this work in any way.

The most intimidating part of the day for Xion was always standing in the literal shadow of Saix, receiving her mission for the day. She supposed it was likely that way for Roxas as well, though she obviously couldn’t know for sure. Maybe Roxas couldn’t be intimidated, what with not having a heart, but that led into questions about herself she didn’t feel like dealing with right now. No, she had to pay attention for now.

Saix looked between her and her blond friend, and then down at a clipboard. “I’m assigning you two together again today. Normally, I would not do such a thing, especially after your string of missions together… it’s inefficient. But your chemistry is… useful, in this case, as this mission won’t involve heart collection.”

Xion tilted her head. “What will it involve, then?”

“Investigation. There’s a new world, and we think the imposter may reside there.”

Xion took a deep breath. The Organization imposter was becoming a problem, and it seemed that Xemnas had the whole Organization out head over heels to murder him. Maybe if they stopped him here, they’d get some respect for once. That’d be nice. Yeah, this would be just fine.

“What do we know about the world already?” Roxas asked.

Saix looked over his notes. “Little. We do know that there appear to be some sort of monsters besides Heartless roaming about. Ignore them, and if they attack, dispose of them quickly and quietly. They are useless to us. We’re calling this place the Spirit World, as it appears to be a common theme with the locals.”

Roxas nodded. “And the rest is for us to figure out?”

“Yes. I expect you two to return with a full report. The imposter’s head on a pike will also do, but somehow, I doubt you’ll find him so easily.” Saix handed the two of them pocket journals and pens to take their notes in. “This is your first investigation mission together without further supervision. Do not disappoint me.”

Roxas and Xion took the paper and bowed their heads. “Yes, sir,” they said in unison.

Saix held out his hand and opened up the Dark Corridor, allowing the two children to pass through. As they approached, however, Saix stopped them for a second. “One more thing. Avoid interaction with the residents as much as possible. If they’re not the imposter, they aren’t worth your time.”

“Yes, sir,” Xion said. She wondered why she needed that spelt out for her after all this time. Perhaps Saix truly trusted her that little. Wouldn’t be the first time.

With that, Saix finally let them go through, onto the new world.

 

** <||||||||||> **

****

The two emerged into what appeared to be a long hallway, with rows of lockers flanking them from the left side. The lights were off, but the hall was perfectly lit by the bright natural light of the sun streaming in from the windows on the right. The hall was empty, but clearly not abandoned—it was clean, and that low hum of electricity you only notice if you listen for it was ringing through the area. This was a place people passed through, often. That much was clear.

Roxas looked to either end of the hallway. “Where is this?”

Xion scratched her chin, thinking. “Some kind of school…? It kinda looks like one of those. I passed by one in Twilight Town, and it looked a lot like this from what I could see through the window.”

Roxas nodded. “Yeah, that makes sense. Is it in session?”

“Probably. I feel like it’s being used right now.” Xion looked out the window, seeing that the sun was low in the sky. “It’s late, though… and quiet. But someone’s definitely still here.”

Roxas pointed to a door ahead of them. “Maybe we can see? The imposter might be here.”

Xion thought for a second, then nodded, crouching down. Roxas did the same, and the two of them crept towards the door, keeping their hoods up. As they approached, they heard voices… but _not_ from the door. They were from around the corner of the hallway to their left. Xion whipped her head around and saw a blond teenager, taller than Roxas, in a school uniform, complete with a tie and a tacky plaid vest. He was looking back around the corner at something.

A girl’s voice called out. “Why are you running from me?!”

The boy called back, with his fist in the air. “I’m not running, this is a tactical retreat! You’ve already proven after multiple fights that I can’t beat you!”

The girl yelled something back, and a loud _thud_ sounded right after. The boy ran, catching sight of Roxas and Xion but pushing them aside like bowling pins. “Excuse me, sorry! Please distract her…!”

Roxas and Xion got up, rubbing their heads, only to be smashed into by the girl. Said girl was overwhelmingly pink—short pink hair, pink cardigan, red glasses. Her shirt and skirt broke that theme, both colored in blue. She was holding what looked like a blood red sword— _A Keyblade?_ Xion thought.

She didn’t have much time to mull on that, though, as the girl was soon grabbing Roxas by the coat and looked ready to stab him straight through the chest.

Roxas frantically waved his hands to try and hold the girl back. “I’m not him, I’m not him!”

The girl stopped and looked him up and down, then quickly realized her confusion and let him go, blushing intensely and bowing. “I’m sorry, so, so, sorry! You really looked like Akihito!”

Xion blinked. “That boy who just ran by? I mean… not really?”

The girl bowed deeper in her shame. “It was the hair that got me!”

Roxas scratched his neck. “Uh, it’s all right… Aren’t you losing him, though?”

The girl blinked, then looked behind her at the other hall. “… _Hey!_ This was a _ruse!_ How unpleasant…!”

“Why are you chasing him anyway?”

She seemed all too able to answer that. “He’s a youmu, and I need to get him.”

Xion tilted her head. “A youmu? Do you mean… like a monster?”

The girl nodded quickly. “Yes, monsters that roam around and cause trouble. He may not look like it, but— _hey, you’re distracting me!”_

Xion cringed and pointed in the direction of the hall. “Then, uh, you really should get going…!”

“Wait. If you’re distracting me, then you might know where he is.” The girl looked behind her, then leaned in. “Take me to him…!”

Xion blinked, then whispered to Roxas. “What do we do…?”

“I don’t think she’ll get off our backs until we help her,” he said. “Let’s get it over with and just keep on with the mission afterwards. Besides, maybe we’ll learn something about this world, if that guy really is one of those monsters.”

“Right.” Xion put on a smile. “Sure, uh, this way…!”

The three of them ran downstairs, and when they couldn’t see Akihito, they ran outside. And there he was, already halfway down the street and running like hell. He looked behind him, eye’s widening when he saw Roxas and Xion. “What are you doing?! I told you to distract Mirai, not come after _me!”_

“Sorry!” Xion called back.

Akihito shook his head and kept running. The girl—apparently Mirai—bolted after him, waving for her two new companions to follow. The three of them ran down the sidewalk, catching up with Akihito within ten meters. Akihito grabbed a trash bin and pushed it in their way, causing Mirai to run straight into it and trip over it, faceplanting on the sidewalk.

Xion leaned down quickly. “Are you okay?”

Mirai pushed herself up, rubbing her face. “How unpleasant…!”

Roxas saw Akihito getting away, and outstretched his hand towards him. _“Deep freeze!”_

At the command, a bolt of ice shot out, landing just short of Akihito’s feet. Akihito jumped, running into a wall. “Yikes—ow!”

Mirai scrambled to standing position and ran over, with Roxas and Xion in tow. The three cornered him by the wall, surrounding him at all sides.

Akihito sighed, closing his eyes in resignation. “All right, all right. You caught me again.”

Mirai pulled the sword back to strike. “That’s right…!”

“Are you three hungry?”

Mirai blinked, then bit her lip. “…Maybe…”

Roxas and Xion looked to each other, then back at Akihito. “Well, we actually kinda have to go,” Xion said. “Maybe another time.”

Akihito nodded. “Fair enough. What are your names, though…? I haven’t seen you two before.”

Mirai looked curious about that, too, so Xion just decided to answer honestly. “I’m Xion.”

“Roxas,” her friend said, nodding.

Akihitio smiled softly. “Interesting names. Can’t say they’re ones I’ve ever heard… but I like them. If you haven’t picked up, I’m Akihito Kanbara, and this is…”

“Mirai Kuriyama!” Mirai nodded quickly to emphasize.”

Roxas nodded. “Uh, thanks… well, uh, see you around, Akihito, Mirai!”

They all exchanged nods, and Roxas and Xion walked off. Xion quickly wrote everything that had just transpired down in her notebook. It was easily enough for a day’s report, at least in her eyes. The two people they had met seemed odd, but they had gotten a tour of the surrounding area through the chase, and they had gotten the info that the monsters were called youmu and could look human. And Mirai’s sword was of note, too—so much info, so many questions.

Roxas looked to her. “Do you think that guy is really a monster? Or a ‘youmu’ or whatever? He looked pretty normal.”

Xion looked back, shrugging. “I guess we’ll have to find out another time. We did say to maybe see him another time.”

Roxas scratched his neck. “Saix did say not to talk to the locals if we can help it.”

“Hey, we’re learning information about this world, right?” Xion smiled. “That’s our job here right now. I’m sure that gathering info is an acceptable reason.”

“I guess.”

“Now, come on. Axel is probably waiting for us, it’s late. Let’s go home.”

 

** <||||||||||> **

****

After hearing the story, Axel laughed. “So Saix tells you not to get involved with the locals, and the first thing you do is help some clumsy pinkette chase a poor teenage boy down the street?”

Xion laughed, too. “It was kind of an accident…!”

“Ah, I know, I know.” Axel took a bite out of his ice cream bar. “That’s why you’ve got to be careful, all right? As soon as you see someone, you need to duck out and hide. Be sneakier next time.”

Roxas leaned in. “What do we do if we, uh, said we could eat sometime…?”

Axel mulled on that for a minute, taking another bite. “…Don’t follow up. You’re not there to make friends. Besides, no one remembers that kind of thing, anyway.”

Xion looked down. “I was hoping we could get more information out of them…”

“Usually, different people get sent if there needs to be followup info.” Axel looked out to the sunset. “Seriously, don’t worry about it.”

The two just nodded, biting into their ice cream bars in unison.                                                                                                                                                                                                         

 


	2. Jet Black

**Summary for the Chapter:**

> Axel and Mirai have a run-in.

**Notes for the Chapter:**

> As a note, the KnK material is going to start diverging heavily from the show from here on out. Besides me not really wanting to just rehash the show, I noticed that KnK is so tightly plotted that it's like a house of cards--breathe on it, and the flow of events collapses, and you get something radically different. Hopefully, I can make the resulting AU here entertaining to read. Enjoy.

Axel leaned back in his chair, hands behind his head, looking Saix right in the eyes. “So, basically, you want me to intimidate children.”

Saix shook his head, clasping his hands together on the desk in front of him. “Absolutely not. That will only create a larger problem than we need.”

“Exactly. So, why did you call me in here, then?”

“Just a little… substantiation.” Saix passed him Xion’s report. “If what she thinks is correct, this world may house much more than the imposter.”

Axel picked up the notes and looked over them. The handwriting was like a chicken with a crayon in its beak, but of course, Xion had already told him everything. Not that he would let Saix know that. Some of the claims were extraordinary… at least, they would be, if there weren’t all the other worlds to compare it to.

He tossed the notes lightly back to the desk. “Don’t see what’s so special about this. Still sounds to me like you’re stressing out over them getting caught up with locals.”

“That’s only part of it.” Saix leaned in. “What interests me about this are mainly what they found out about the children. The sword doesn’t interest me, I feel that was a bit of a stretch. But these ‘youmu’… it seems they can, in fact, be intelligent. They may be more relevant than we first believed.”

Axel shrugged. “Then they’re just locals, no?"

“Do remember that in both the initial scouting and the Keybearer’s investigation, there were no Heartless reported. But a world without Heartless doesn’t line up with what we know about how worlds open up to travel. So, logically… we might just be missing Heartless right before our eyes.”

Axel mulled on that. “…So, what, you want me to kill the blond kid and see if a heart comes out?”

“That will be Roxas’s job… if this theory is correct.” Saix pulled back into proper posture. “ _Your_ job is to observe. Preferably, _without_ getting involved as they did.”

“So just see how they act, then.”

Saix nodded. “Correct. Stay they for a few days and report back.”

“…All right, fair enough. Might as well get it over with, then.”

Axel stood up and opened the Dark Corridor himself. Saix stood up as well, but he didn’t say anything. After a short pause, Axel shrugged and silently slipped in. This was how a lot of their interactions were going lately, he noticed. Very professional, almost military. Very cold. It was a wonder they talked at all anymore.

**0=0=0=0=0=0**

Mirai had elected to go home alone this time around. She couldn't rely on Akihito forever. The fact that he had been so willing to help her out lately was nice, but ultimately, it wouldn't last. She knew that, because it never did. Not since what had happened. What she had done.

The Hollow Shadow would be coming soon. Or coming back, as it were. Maybe she could go back to him after she defeated it, atoned for the life that her hands had helped that youmu end.

She heard something behind her, interrupting her thoughts. Almost like a gust of wind... but it wasn't a windy day, and she couldn't feel the gust or see anything looking like it had just been blown. She turned around to see where it had come from.

Right there was a tall man in a black hood.

She thought back to those kids who had helped her chase down Akihito in the first place--Roxas and Xion, right? This man had the same coat. But this... this was different. The man was brooding, intimidating, powerful.

Mirai called out. "Who are you?"

The man didn’t say anything, instead ducking into an alleyway. Mirai called again, louder. "Hey! Come back! You look like people I met...!"

But alas, the man didn't call back. Mirai looked back and forth between the route to her home and the alley that he had run into.

Then she shook her head. It would be safer to avoid seeing that man again, whoever he was and whatever his intentions were. If she didn't get involved, she wouldn't be in any crossfire. And after all, she did need to survive long enough to fight the Hollow Shadow.

**0=0=0=0=0=0**

If at all possible, Axel planned to avoid catching the eyes of that girl again. Mirai, that's what Xion had said her name was. She seemed like a liability. He doubted Xion's claims that she had a Keyblade, based on the description of the weapon--sure, there were some odd ones about, but none of them resembled a blood-red sword.

And with that put aside, there was really no reason to investigate her further, except perhaps as a gateway to this Akihito character. And that would be easy enough to pull off without being seen--just shadow her until she found the tall Roxas.

And, oh, was she so easy to shadow. At first.

He started early the next day, catching her passing by the same alleyway from the day before and blending himself into some of the morning crowd. Mirai seemed constantly distracted, as if her mind were someplace else. Occasionally, she would pull out her phone and frantically type something, even narrating it. First a complaint, and after that, what sounded like angry responses to trolls.

_How cute,_ he thought. _Pays more attention to the haters than to the people around her._

But a few hours there was a shift in her awareness. Axel knew exactly when he had been spotted—Mirai’s eyes widened, and she picked up the pace considerably. Axel shook his head—he had let his guard down too much. He had to change plans.

He quickly slipped out of the crowd and opened up a Dark Corridor up onto the rooftops. He was able to spot Mirai again quickly—the shade of her hair dye would have made Marluxia blush. It only became easier when she left the crowd herself for an empty stretch of road. He just had to turn the corner and—

Oh. It was blocked off. Axel could see it clearly, even though no one else seemed to notice it—a bright, blue shimmer that appeared after Mirai had passed through, encircling a large area and extending into the sky.

Axel raised an eyebrow and walked around, inspecting the barrier. It didn’t look like the ones the Organization used to designate the area of operations. That meant it had to be of this world—and if it was of this world, it could be circumvented.

He hopped down, off the roof and down to the entrance to the side street that Mirai had passed into. Then he snapped his fingers, opening up a new Dark Corridor, a short one that would just get past the barrier. An Organization barrier would have easily short-circuited such an easy maneuver… but with this one, Axel was able to pass through just fine.

Axel smiled to himself a bit at that. But the accomplishment was soon dampened when he realized that he had completely lost Mirai. He shook his head and flipped his hood down. “Dammit…”

He would have to approach this another way. And another day.

**0=0=0=0=0=0**

Mirai knew for sure now that she was being watched.

What for, she had no clue. But interacting with those kids had been a mistake. Whoever they worked for, she had been marked.

She couldn't prepare for the fight ahead unless she could get these people off her back first. Yet another thing she had to face alone.

She paced up and down her tiny studio apartment, occasionally looking out the window to see if the man was out there. Dammit, even she couldn't face this one alone. It was too much. But who was supposed to turn to?

...Akihito. Dammit, she didn't have any better ideas.

She pulled out her phone and skimmed down her contacts to the number. She hadn't actually called the boy once since they exchanged that number--she was on her phone a lot, but she was not the type to make calls. it was awkward, clumsy. A layer of unpleasantness on top of the unpleasantness of talking to people in the first place.

She shook her head and just hit the button, putting the phone to her ear. After a few seconds that felt like they dragged on for ages, she heard the other end pick up.

Akihito's voice came through. "Hello...Kuriyama?"

"Yes, yes, it's me..." Mirai laid down on her bed, holding her head.

Akihito sounded concerned. "I didn't know you did phone calls..."

"Senpai, I think I'm being stalked."

"Wh-what?" Akihito sounded outright shocked at that. "By who?"

Mirai looked to the window. "Some guy in a black coat... the same one those people we met were wearing before. I saw him following me today. I wouldn't want to bother you normally, but..."

"No, no, you are not bothering me." Mirai heard a rustling, like hangers moving in a closet. "I'm coming over."

Mirai bit her lip. "Senpai, thank you, but... I don't think there's enough room in here for you to stay the night..."

“Then we can go to…  I don’t know, Ayaka,” Akihito said. “Maybe these black hood people are youmu, and if they are, she’ll know better than anyone.”

Mirai thought on that, looking to her hand and clutching the bandage on her arm a few times. “…I just don’t want to get anyone caught in this and make it worse.”

“I know. But dammit, I can’t just leave you to be followed around by some creep or a youmu.” The ambient noise on the other end picked up as Akihito left his apartment. “Just stay there, I’ll be there as fast as I can.”

The call ended. Mirai rubbed her face and looked out the window again.

She turned off the light when she noticed black coattails , moving in the wind as if their owner was running away from the window.


End file.
